Patent Document 1 discloses an example of an axially yielding elasto-plastic hysteresis brace. In this brace, a steel core (steel-made central axial-force member) is configured with plates, an outer periphery of the steel core is covered via an unbonded layer (anti-adhesive film) with a concrete buckling-restraining member (buckling-restraining concrete), and an outer periphery of the buckling-restraining member is covered with a steel pipe (steel member), thereby reinforcing the steel core.
In this case, the steel core has a minus (−) type or plus (+) type (cross type) cross-section. An end of the steel core is formed in a cross shape so as to be greater in cross-sectional area and cross-sectional coefficient than a central portion of the steel core in the longitudinal direction in order that the steel core will not undergo plastic deformation by an axial force or is able to resist a bending moment.